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Please help! i'm overdue with project and i can't get my mic to connect properly. ok so here is what i have. PLEASE tell me if i have anything wrong. I want to hook up a sound sensor to a A/D converter. i have a 2 pin panasonic elec condenser microphone (~5v rated, 60dB sig-noise ratio, +/- ~40dB sensitivity). This plugs into a Jameco preamp(http://www.jameco.com/cgi-bin/ncommerce3/ExecMacro/jameco/searchResult.d2w/report?sort=BKW&search=preamp) which has "Output impedance: 1 kilo ohm Max. input signal: 40mV Frequency range: 20Hz-20kHz +/-3dB". from here, i'm guessing the signal will be boosted but i have no clue in what range. anyways, then i hook it up to the A/D with this circuit(http://groups.yahoo.com/group/basicx/message/3815) to convert the AC wave into a linear DC signal. I'm using a 10bit A/D built into a BasicX controller. I have no clue what i'm doing, so anyone, PLEASE GIVE ME ADVICE as to whether this will work, or if you have suggestions! __________________________________ |
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microphone attach to microcontroller
Started by ●August 6, 2003
Reply by ●August 6, 20032003-08-06
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Jack, You are on the right track -- but I know you are in a hurry -- so this is quick and dirty. I think you would do better to use a dynamic mic element instead of the condenser mic, unless you know what you are doing to get the dc voltage to the mic, and the ac signal back out of the mic. Go to radio shack and buy a couple of 1/8" mini jacks. Wire one of them to the input of the preamp. Pay attention to the ground and hot wires. Hot hooks to the "tip" connection. Plug a cheap dynamic mic (that costs 5 bucks or less) into the input. if you can not quickly locate a dynamic mic, use a set of ear buds as a mic -- they will work OK in place of a mic -- only the left ear bud will connect to a mono 1/8" jack. Quality does not seem important, so the earbud should work good enough. temporarily hook the preamp output the other 1/8" jack and plug a set of headphones into the jack --- a speaker will be too heavy of a load on this preamp. turn the volume control down on the preamp -- power up the preamp. Make sure you are getting signal through the preamp and that you can hear in the headphones. Once you are sure you are getting signal through the preamp -- unhook the headphones -- they will reduce the output voltage too much, and could keep the preamp from putting out enough voltage for your circuit. Now get a full wave bridge rectifier or wire 4 diodes like a full wave rectifier. Hook that to the output of the preamp. Get a volt meter and hook to the output of the rectifier -- set the meter to DC voltage 3 volt or greater range. now talk, then yell into the mic. adjust the preamp volume so that you measure about 3 volts when you yell. This is critical, because if you set this volume too high, you will destroy the input pin of the BX-24. It would be smart to connect a 10k or 4.7k resistor across the input of the BX-24 pin. It would be even smarter to connect a 5 v zener diode across the input. Now -- hook the output of the rectifier to the BX-24, paying attention to ground and hot. Say your prayers then give it the smoke test. If you power it up -- and it project does not let the smoke out of the circuit -- you did good! Good Luck, Paul Little in Texas -- it was 101 degrees here today. ----- Original Message ----- From: Jack Wu To: ; Sent: Wednesday, August 06, 2003 11:52 AM Subject: [BasicX] microphone attach to microcontroller Please help! i'm overdue with project and i can't get my mic to connect properly. |
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Reply by ●August 7, 20032003-08-07
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hi. thanks a lot. i just ordered 2 different VOX sets from hobbytron OVERNIGHT. i looked at the plans, and basically the VOX kits are microphone driven relay switches. Basically it has everything i need except i don't need the voltage comparator nor the relay. So basically the mic connects to an amp stage(1 or 2 op amps) which amps the signal. This connects to diodes which is a half wave rectifier(as it says). i don't know what the outputs are but hopefully they fall within 0-5v. I'm just going to use these portions of the kit. Thanks very much, let me know if this idea is wrong. my backup plan is to use the 15level sound level meter kit that i also bought from them. it is very rudimentary, but oh well wtf. i HAVE to get this project done! DOH! so once i have a DC signal from the kits, is there anything else i need to worry about? like the current being too much, or the impedance sucking or something like that? -Jack btw check out www.infostomp.com. it's my website for college admissions help. :-) --- Paul Little <> wrote: > Jack, > > You are on the right track -- but I know you are in > a hurry -- so this is quick and dirty. > > I think you would do better to use a dynamic mic > element instead of the condenser mic, unless you > know what you are doing to get the dc voltage to the > mic, and the ac signal back out of the mic. > > Go to radio shack and buy a couple of 1/8" mini > jacks. Wire one of them to the input of the preamp. > Pay attention to the ground and hot wires. Hot > hooks to the "tip" connection. > > Plug a cheap dynamic mic (that costs 5 bucks or > less) into the input. if you can not quickly locate > a dynamic mic, use a set of ear buds as a mic -- > they will work OK in place of a mic -- only the left > ear bud will connect to a mono 1/8" jack. Quality > does not seem important, so the earbud should work > good enough. > > temporarily hook the preamp output the other 1/8" > jack and plug a set of headphones into the jack --- > a speaker will be too heavy of a load on this > preamp. > > turn the volume control down on the preamp -- power > up the preamp. > > Make sure you are getting signal through the preamp > and that you can hear in the headphones. > > Once you are sure you are getting signal through the > preamp -- unhook the headphones -- they will reduce > the output voltage too much, and could keep the > preamp from putting out enough voltage for your > circuit. > > Now get a full wave bridge rectifier or wire 4 > diodes like a full wave rectifier. Hook that to the > output of the preamp. Get a volt meter and hook to > the output of the rectifier -- set the meter to DC > voltage 3 volt or greater range. > > now talk, then yell into the mic. > > adjust the preamp volume so that you measure about 3 > volts when you yell. This is critical, because if > you set this volume too high, you will destroy the > input pin of the BX-24. It would be smart to > connect a 10k or 4.7k resistor across the input of > the BX-24 pin. It would be even smarter to connect > a 5 v zener diode across the input. > > Now -- hook the output of the rectifier to the > BX-24, paying attention to ground and hot. > > Say your prayers then give it the smoke test. If > you power it up -- and it project does not let the > smoke out of the circuit -- you did good! > > Good Luck, > Paul Little > in Texas -- it was 101 degrees here today. > ----- Original Message ----- > From: Jack Wu > To: ; > > Sent: Wednesday, August 06, 2003 11:52 AM > Subject: [BasicX] microphone attach to > microcontroller > Please help! i'm overdue with project and i can't > get > my mic to connect properly. > [Non-text portions of this message have been > removed] __________________________________ |
